Installations of this nature are already known and they are used in particular for manufacturing elongate building elements, such as beams, posts, piles, etc. or plate-shaped building elements such as slabs or pre-slabs.
Pre-slabs are thin, generally planar elements of prestressed or reinforced concrete acting as non-reusable shuttering, which are used in particular when making floors. A pre-slab is placed in its final position in a building and is then covered with a layer of concrete which, after hardening, constitutes together with said pre-slab a strong slab of greater thickness.
At present, pre-slabs are manufactured either on site, or else they are prefabricated in a prestressed pre-slab factory.
When they are made on site, problems associated with the maximum size of load which can be transported by road are avoided, but the performance of the manufacturing process and any possibilities of rationalizing production remain limited.
When elements are made in a factory, they may be made to have large dimensions, in particular the elements may be at least 2.5 meters wide, thereby enabling wide spans to be covered.
Although such factory manufacture is theoretically suitable for automatic industrial manufacturing techniques, it turns out, in practice, that it is constrained by various special problems.
Such problems stem from the fact that each pre-slab constitutes a specific component part of a building and may differ from other pre-slabs in its dimensions, in its reinforcing rods, and in the inserts and spaces that need to be provided therethrough.
This problem is made even more difficult by the fact that the manufacturing area of an installation generally extends over a length of several tens of meters, for example, over 100 meters, and over a width which generally lies in the range 2.5 meters to 3 meters.
Thus, before casting the concrete, the locations of the pre-slabs on the manufacturing area need to be accurately delimited so that the sets of molds can be properly placed and with as little loss of room as possible on the manufacturing area.
One of the aims of the present invention is to improve the manufacture of prestressed or reinforced concrete elements, and in particular of prestressed concrete slabs or pre-slabs, by automating the various manufacturing steps as much as possible, and in particular by automating the tracing steps.